Low-power μ wave plasma source for microsystems

Abstract

Summary form only given, as follows. Microplasma sources can be integrated within portable devices for applications such as bio-MEMs sterilization, small-scale materials processing, and micro chemical analysis systems. Portable operation of microplasma sources, however, places a limit on the amount of power and the vacuum levels that can be employed in the plasma source. A low-power microwave plasma source based on a microstrip split-ring resonator has been fabricated and characterized. The microstrip is formed in the shape of a 16-mm i d ring with a 500-/spl mu/m gap in which the discharge is formed The plasma source operates at 900 MHz and presents a quality factor of Q = 335. This quality factor is an order of magnitude greater than in microfabricated inductively coupled plasma sources operating in the same frequency range. The high Q value of the plasma source allows low-power (high-efficiency) operation up to atmospheric pressure. Argon and air discharges can be self-started with less than 3 W in a relatively wide pressure range. At low pressure, the discharge forms a diffuse plasma that extends beyond the discharge gap in the split-ring resonator.